Abstract

Poly((methacryloylamino)propyl trimethylammonium chloride-co-vinylimidazole) (p(MAPTAC-co-VI)) hydrogels were synthesized through free radical polymerization of 3-(methacryloylamino)propyl trimethylammonium chloride (MAPTAC) and 1-vinylimidazole (VI) in aqueous solutions with ammonium persulfate (APS) used as initiator and N,N′-methylenebis(acrylamide) (MBA) as the crosslinking agent. By modifying with HCl, the positive charge density on the hydrogel network structure was increased and quaternized hydrogels (p(MAPTAC-co-VI)-q) were obtained. Traditional swelling and spectrophotometric characterization techniques were used to gain a better understanding of the performance of cationic hydrogels for the removal of anionic dyes. FTIR, SEM, and EDX confirmed the structure of the hydrogel before and after the adsorption process. Later, dye adsorption performance of these p(MAPTAC-co-VI)-q hydrogels was investigated under different adsorption conditions, including initial concentration, temperature, pH values of dye solutions, and adsorption contact time, adsorbent dosage and in real water samples. Various isotherm and kinetic models of dye adsorption by the hydrogel were also studied and the experimental adsorption followed a pseudo-second order model and fitted the Langmuir isotherm well. Thanks to the effective use of existing adsorption sites, high adsorption capacity was achieved for eriochrome black T (EBT) and methyl orange (MO) dyes. The values of q_max are as follows: 1818.2 mg/g and 1449.3 mg/g, respectively. Thermodynamic parameters indicate that the process was spontaneous and endothermic. P(MAPTAC-co-VI)-q hydrogels can be used as a potential adsorbent for removal of anionic dye molecules, one of the industrial pollutants, from wastewater.

摘要

由 3-(甲基丙烯酰氨基)丙基三甲基氯化铵 (MAPTAC) 和 1-乙烯基咪唑 (VI) 在以过硫酸铵 (APS) 为引发剂和N,N的水溶液'-亚甲基双（丙烯酰胺）（MBA）作为交联剂。通过用HCl改性，水凝胶网络结构上的正电荷密度增加，得到季铵化水凝胶(p(MAPTAC-co-VI)-q)。传统的溶胀和分光光度表征技术用于更好地了解阳离子水凝胶去除阴离子染料的性能。FTIR、SEM 和 EDX 证实了吸附过程前后水凝胶的结构。随后，研究了这些 p(MAPTAC-co-VI)-q 水凝胶在不同吸附条件下的染料吸附性能，包括初始浓度、温度、染料溶液的 pH 值、吸附接触时间、吸附剂用量和真实水样。还研究了水凝胶吸附染料的各种等温线和动力学模型，实验吸附遵循准二级模型，很好地拟合了朗缪尔等温线。由于有效利用了现有的吸附位点，对铬黑 T (EBT) 和甲基橙 (MO) 染料实现了高吸附容量。q 的值_最大值如下：分别为 1818.2 mg/g 和 1449.3 mg/g。热力学参数表明该过程是自发的和吸热的。P(MAPTAC-co-VI)-q 水凝胶可用作从废水中去除阴离子染料分子（工业污染物之一）的潜在吸附剂。